Conventional wastewater treatment systems have a number of disadvantages. Some wastewater treatment processes can require lengthy microbial digestion processes that may last weeks. Plants that implement such processes require high-capacity, high energy-consuming, expensive equipment. Wastewater treatment can also require the addition of various chemicals to assist in separating the solids found in waste-activated sludge. These chemicals can include dewatering agents, thickening agents, flocculants and the like. Chemical costs can be significant. Some chemicals can remain in treated waste in undesirable concentrations.
Disposal of the treated waste can also be problematic. Transporting sludge from wastewater treatment plants to landfills, and burying the sludge, are expensive, time-consuming processes that often have negative environment impact. Sludge buried in landfills can release methane gas into the atmosphere. Effluent released into rivers and oceans often contains high levels of ammonia and other deleterious substances which can be harmful to the environment.
Various wastewater treatment methods and methods for dealing with sludges are described the following United States patents:                U.S. Pat. No. 3,342,731 (Gotthold)        U.S. Pat. No. 3,428,554 (Dye)        U.S. Pat. No. 3,440,165 (Davis et al.)        U.S. Pat. No. 3,549,529 (Wiseman)        U.S. Pat. No. 3,728,254 (Carothers)        U.S. Pat. No. 3,803,806 (Komline Sr.)        U.S. Pat. No. 4,028,130 (Webster et al.)        U.S. Pat. No. 4,297,122 (Wallace)        U.S. Pat. No. 4,554,002 (Nicholson)        U.S. Pat. No. 4,778,598 (Hoffman et al.)        U.S. Pat. No. 4,541,933 (Armold et al.)        U.S. Pat. No. 4,917,802 (Fukaya et al.)        U.S. Pat. No. 5,078,882 (Northrop)        U.S. Pat. No. 5,336,290 (Jermstad)        U.S. Pat. No. 5,482,528 (Angell et al.)        U.S. Pat. No. 5,853,590 (Burnham)Another water treatment process is described in GB 2216114A.        
There is a need for cost-effective, environmentally friendly, wastewater treatment systems that reduce or avoid disadvantages of existing wastewater treatment systems.